Acarofauna associada a cocos nucifera l. variedade anão verde e manejo com fungos entomopatogênicos na Amazônia brasileira

Abstract

The coconut crop (Cocos nucifera L.) suffers attacks from pests at all stages of development, especially phytophagous mites that attack the fruits and reduce productivity, especially Aceria guerreronis Keifer (Eriophyidae) and Steneotarsonemus furcatus (Tarsonemidae). Several chemical products are registered for the control of A. guerreronis, however, this pest inhabits the perianth of the fruit, protected by the bracts, making control difficult. Since the market has become more demanding for more sustainable products, predatory mites and entomopathogenic fungi are important in the integrated management of these pests. In this context, the objective was to identify the mite fauna in the fruits of green dwarf coconut palm plants, through the study of the population fluctuation of A. guerreronis, S. furcatus and predators, and the molecular identification of entomopathogenic fungi and evaluation of the potential and cost application of these fungi as an alternative to control A. guerreronis. The study was conducted in a commercial green dwarf coconut plantation located in the municipality of Santa Izabel do Pará-Pará. Monthly collections of fruits, with and without injuries caused by mites, from clusters 13 to 17, were carried out. In the bunches, 8,818 fruits were evaluated, of which, 88.31% were without injuries, 7.25% were with injuries caused only by A. guerreronis, 3.24% by S. furcatus and 1.17% with both injuries in the same fruit. Aceria guerreronis represented 99.75% of the 563,170 mites collected, S. furcatus was collected from only 87 fruits. Predatory mites of the Phytoseiidae family were the most abundant, eight species were identified, Amblyseius aerialis (Muma) being the predominant one. The fungi Metarhizium anisopliae, Trichoderma sp., Beauveria bassiana, Purpureocillium lillacinum, a chemical acaricide based on abamectin, were tested ad at a concentration of 108 conidia/ml on coconut fruits with the presence of pest mites. The fruits treated with P. lillacinum had a lower number of mites and a higher number of fruits not infested by A. guerreronis, considering this the best treatment, however, the treatment with B. bassiana also stood out. This work provides important information about the diversity, abundance and population fluctuation of natural enemies in coconut trees and fungal species with potential for the control A. guerreronis.